Architecture

OxideBBS is a Rust modular monolith. It ships as one primary server binary with small internal crates for focused boundaries.

Telnet Listener
    |
Transport
    |
Session
    |
Menu / Command Router
    |
Core Services
    |
DecentDB Repository Layer

Door execution follows a separate path:

Session
    |
Door Service
    |
Node Manager
    |
Drop File Writer
    |
Door Runner
    |
DOSEMU2 Runtime
    |
PTY/COM1 Bridge

Constraints

• Use Rust.
• Use DecentDB as the only system database.
• Keep v1 telnet-only.
• Treat ANSI/CP437 as a first-class byte-oriented terminal format.
• Do not use Ratatui for the remote caller UI.
• Keep door execution isolated from core session logic.
• Do not bundle copyrighted or abandonware DOS doors.

Terminal Profiles

The remote caller UI must support both 80-column and 40-column terminal profiles. Menus, prompts, status bars, wrapping, paging, and ANSI assets should fit the active terminal width without corrupting CP437 art or truncating commands.

Menus

Menus are configured as safe key-to-action mappings. Screen assets draw the visual menu, while menu entries decide what a pressed key does. The current implementation also includes pure core flows for new-user creation, login state updates, local message commands, private mail targeting, moderation state changes, and FTN/OxideNet address and packet-boundary models. Door support has tested drop-file generation, per-node runtime directories, dry-run planning, DOSEMU2 command planning, and DecentDB run logging helpers.

Door byte bridge model

Door launch is separated from caller transport logic.

caller telnet client
  <-> OxideBBS caller transport
  <-> OxideBBS PTY byte bridge
  <-> DOSEMU2 COM1 pts backend
  <-> DOSEMU2-emulated COM1 UART
  <-> DOS door program

OxideBBS owns Transport and bridge ownership during door sessions. DOSEMU2 remains an isolated runtime that receives caller bytes over a host PTY file and presents them as COM1 UART bytes. This is not a Rust-hosted FOSSIL driver. A DOS-side FOSSIL TSR may be loaded by a specific door if that door requires FOSSIL APIs.